Wireless local area networks (Wlan`s) are based on the 802.11 protocol and have become the standard for wireless connectivity. These networks are generally called wi-fi. The new IEEE physical standard (802.11n) made possible the support distribution of high-throughput applications like video streaming. Wi-fi networks however are prone to RF (radio-frequency) interference that can significantly affect the performance of wlan`s. In order to minimize WLAN downtime an IT administrator need both real-time and historical data from RF interference to diagnose the network`s performance.
Well-known interferers with WI-FI networks.
A wi-fi network uses the unlicensed 2.5 and 5 GHz frequency bands which they share with other devices. Except Bluetooth devices, no other devices have the capability to work together with the wi-fi networks thus when an interfering device transmits energy in the channel that a WLAN is using for communication, it significally affects the network.
Here are some devices that commonly interfere with wlan`s:
- wireless video cameras
- analog cordless phones
- DSSS digital cordless phones
- wireless game controllers
- conventional microwave ovens
- FHSS digital cordless phones
- inverter microwave controllers
- motion detectors
- bluetooth devices
- wireless baby monitors
RF interference degrades wi-fi network signal
The interference of RF devices on Wi-fi networks depends on the type of the interferer, the RF characteristics of the devices and the positioning of the interferer towards the wlan device. The tests revealed that interferences can degrade wlan signal from 10% to 100%, depending upon the location and the type of interferer. All the devices mentioned above were responsible for signal losses up to 100%, only the bluetooth device showed a minimal 4% signal loss.
Interferences threaten the wireless network security
As wlan`s support more and more applications like voice and video communications, security issues must be kept under control as interferences may come from an intentional, malicious interferer or from an unintentionate source like a cordless phone. It is vital that a wireless local area network to be permanently monitored so that RF interferences are discovered instantly and real-time alerts are send to network administrators.